Dry eyes occur when there is not enough good quality tears to lubricate the eyes. The medical term for it is keratoconjunctivitis sicca. Tears are important as they supply the eyes with nutrients and protect them by keeping them wet. Also, they refract or concentrate the light to help us see better.
As a general rule, if eyes are dry in the morning after the eyes have been closed overnight, blepharitis is the problem. If eyes become dry throughout the day, then evaporation of tears from the eye's surface is the cause.
When to see a doctor
If you experience severe eye pain, very red eyes or loss of vision.
See our guide to choosing eye drops.
You can also find some great information about dry eyes and eye drops on the Eye Drop Database.